Search Results (682)

Introduction: Performance in a single step has been suggested to be a sensitive measure of movement quality in pediatric clinical populations. Although there is less information available in children with typical development, researchers have postulated the importance of analyzing the effect of body weight modulation on the initiation of stair ascent, especially during single-limb stance where upright stability is most critical. The purpose of this study was to investigate the effect of load modulation from −20% to +15% of body weight on typical pediatric lower limb joint moments during a step-up task. Methods: Fourteen participants between 5 and 21 years who did not have any neurological or musculoskeletal concerns were recruited to perform multiple step-up trials. Peak extensor support and hip abduction moments were identified during the push-off and pull-up stance phases. Linear regressions were used to determine the relationship between peak moments and load. Mixed-effects models were used to estimate the effect of load on hip, knee, and ankle percent contributions to peak support moments. Results: There was a positive linear relationship between peak support moments and load in both stance phases, where these moments scaled with load. There was no relationship between peak hip abduction moments and load. While the ankle and knee were the primary contributors to the support moments, the hip contributed more than expected in the pull-up phase. Discussion: Clinicians can use these results to contextualize movement differences in pediatric clinical populations, including in those with cerebral palsy, and highlight potential target areas for rehabilitation for populations such as adolescent athletes. Full article

Background/Objectives: The iliopsoas muscle plays an essential role in lumbopelvic and hip anterior stability, which is particularly important in the presence of limited osseous acetabular coverage anteriorly as in hip dysplasia and/or hip micro-instability. The purpose of this systematic review is to (1) describe iliopsoas activation levels during common rehabilitation exercises and (2) provide an evidence-based exercise progression for strengthening the iliopsoas based on electromyography (EMG) studies. Methods: In total, 109 healthy adult participants ranging from ages 20 to 40 were included in nine studies. PubMed, CINAHL, and Embase databases were systematically searched for EMG studies of the psoas, iliacus, or combined iliopsoas during specific exercise. The Modified Downs and Black Checklist was used to perform a risk of bias assessment. PROSPERO guidelines were followed. Results: Nine studies were included. Findings suggest that the iliopsoas is increasingly activated in ranges of hip flexion of 30–60°, particularly with leg lowering/raising exercises. Briefly, >60% MVIC activity of the iliopsoas was reported in the active straight leg raise (ASLR) in ranges around 60° of hip flexion, as well as with supine hip flexion and leg lifts. In total, 40–60% MVIC was found in exercises including the mid-range of the ASLR around 45° of hip flexion and lifting a straight trunk while in a hip flexed position. Conclusions: The findings suggest that exercises in increased hip flexion provide greater activation of the iliopsoas compared to exercises where the trunk is moving on the lower extremity. Iliopsoas activation can be incrementally progressed from closed to open kinetic chain exercises, and eventually to the addition of external loads. The proposed exercise program interprets the results and offers immediate translation into clinical practice. Full article

(1) Background: Imageless computer navigation systems have the potential to improve the accuracy of acetabular cup position in total hip arthroplasty (THA). Popular imageless navigation methods include locating the patient in a three-dimensional space (registration method) while using a baseline to angle the acetabular cup (reference plane). This study aims to compare the accuracy of different methods for determining postoperative acetabular cup positioning in THA via the direct anterior approach. (2) Methods: Fifty-one participants were recruited. Optical and inertial sensor imageless navigation systems were used simultaneously with three combinations of registration methods and reference planes: the anterior pelvic plane (APP), the anterior superior iliac spine (ASIS) and the table tilt (TT) method. Postoperative acetabular cup position, inclination, and anteversion were assessed using CT scans. (3) Results: For inclination, the mean absolute error (MAE) was lower using the TT method (2.4° ± 1.7°) compared to the ASIS (2.8° ± 1.7°, p = 0.17) and APP method (3.7° ± 2.1°, p < 0.001). For anteversion, the MAE was significantly lower for the TT method (2.4° ± 1.8°) in contrast to the ASIS (3.9° ± 3.2°, p = 0.005) and APP method (9.1° ± 6.2°, p < 0.001). (4) Conclusion: A functional reference plane is superior to an anatomic reference plane to accurately measure intraoperative acetabular cup inclination and anteversion in THA using inertial imageless navigation systems. Full article

A gait analysis serves as a critical tool for examining the biomechanical differences in movement patterns between trained and untrained individuals. This study investigates the nuanced differences in gait patterns between professional ballet dancers and non-dancers, with a focus on angular velocities and accelerations across key body joints. By analyzing the positions and movements of the head, neck, shoulder, spine, hip, knee, and ankle in both the sagittal (SP) and frontal (FP) planes, the study aims to identify key distinctions in joint dynamics that arise from differing levels of physical training. The study involved ten participants in total, comprising four professional female ballet dancers and six non-dancer students (three males and three females). In the first experiment, participants performed walking trials at five different speeds, while in the second experiment, the ballet dancers performed six distinct dance routines. Data were captured using a Kinetics motion capture camera system, which recorded the maximum and minimum angular velocities and accelerations during both walking and dancing. Key findings reveal significant differences in joint dynamics. For example, non-dancers’ right shoulder exhibited a maximum angular velocity of −0.47 rad/s and a minimum of 0.71 rad/s, while dancers showed a maximum of −0.09 rad/s and a minimum of 0.07 rad/s. The right knee also displayed notable differences, with angular velocities ranging from −3.88 rad/s to 2.61 rad/s for non-dancers, compared to −0.35 rad/s to 0.54 rad/s for dancers. In terms of acceleration, dancers’ left shoulder reached a maximum of 3.952 mm/s², while their right shoulder had a minimum of −0.1 mm/s². For non-dancers, the left elbow showed a maximum acceleration of 2.997 mm/s², while the right elbow had a minimum of 0.05 mm/s². These variations in angular velocity and acceleration underscore the distinct roles and movements of various joints, highlighting differences in muscle coordination and joint control. Understanding these patterns is crucial for assessing joint function, optimizing training, and developing intervention strategies for injury prevention and rehabilitation. The findings hold significant implications for the dance community and other physically active populations, offering valuable insights into performance enhancement and movement health. Full article

Background: Gait and posture analysis plays a crucial role in understanding human movement, with significant applications in rehabilitation, sports science, and clinical settings. The GaitON^® system, a 2D motion analysis tool, provides an accessible and cost-effective method for assessing gait and posture. However, its reliability in clinical practice, particularly for intra-rater consistency, remains to be evaluated. This study aims to assess the intra-rater reliability of the GaitON^® system in a healthy population, focusing on gait and posture parameters. Methods: A total of 20 healthy participants (10 males and 10 females) aged 18 to 50 years were recruited for the study. Each participant underwent gait and posture assessments using the GaitON^® system on two separate occasions, spaced one week apart. Video recordings from anterior and posterior views were used to analyze gait, while images from anterior, posterior, and lateral views were captured to assess posture with markers placed on key anatomical landmarks. The reliability of the measurements was analyzed using intraclass correlation coefficients (ICC), a standard error of measurement (SEM), and the smallest detectable difference (SDD) method. Results: The GaitON^® system demonstrated excellent intra-rater reliability across a wide range of gait and posture parameters. ICC values for gait parameters, including hip, knee, and ankle joint angles, ranged from 0.90 to 0.979, indicating strong consistency in repeated measurements. Similarly, ICC values for posture parameters, such as the head alignment, shoulder position, and ASIS alignment, were above 0.90, reflecting excellent reliability. SEM values were low across all parameters, with the smallest SEM recorded for the hip joint angle (0.37°), and SDD values further confirmed the precision of the system. Conclusion: The GaitON^® system provides reliable and consistent measurements for both gait and posture analysis in healthy individuals. Its high intra-rater reliability and low measurement error make it a promising tool for clinical and sports applications. Further research is needed to validate its use in clinical populations and compare its performance to more complex 3D motion analysis systems. Full article

Phthalates are commonly found in indoor environments. Consequently, children may be exposed to phthalates through the air, potentially causing health issues. We collected 72 air samples from 60 households and 12 classrooms in Jinan, surveyed and health-examined children, assessed their phthalate inhalation exposure, and analyzed the associations between inhalation exposure levels and children’s anthropometric and physiological indicators. Eight phthalates were detected in children’s households and classrooms, with detection frequencies ranging from 91.6% to 100%. Di-iso-butyl phthalate (DiBP), di-n-butyl phthalate (DnBP), and di (2-ethylhexyl) phthalate (DEHP) were the predominant phthalates. Children’s indoor inhalation exposure to phthalates ranged from 8.90 to 147 ng/(kg·day), with DEHP being the main inhaled phthalate. The non-carcinogenic risks of indoor environments where children live are within acceptable limits. DEHP has a low carcinogenic risk. Di-n-octyl phthalate (DnOP) exposure was associated with a decrease in body mass index z-score, waist circumference, and hip circumference. Additionally, DEHP exposure was negatively associated with the waist-to-hip ratio. DiBP exposure was negatively associated with the systolic blood pressure z-score, while DnOP exposure was negatively associated with the diastolic blood pressure z-score. Furthermore, DEHP exposure was positively associated with fractional exhaled nitric oxide z-score. The findings of this study suggest that phthalate inhalation exposure may substantially affect various health metrics in children, including body mass index, waist and hip circumference, and blood pressure, and increase the risk of respiratory tract inflammation. Full article

High-altitude landing maneuvers can pose a significant injury risk, particularly when performed with different landing techniques. This study aims to compare the biomechanical parameters and injury risks associated with two landing positions—staggered foot landing and simultaneous bilateral landing—using Xsens inertial units and electromyography (EMG) sensors. A total of 26 university students (13 males, 13 females) participated in this study. Kinematic data were collected using inertial measurement units (IMUs), muscle activity was recorded with EMG, and ground reaction forces were captured using 3D force plates. The data were processed and analyzed using the AnyBody modeling system to simulate joint forces, moments, and muscle activation. This study found that simultaneous bilateral landing exhibited greater hip flexion-extension, knee flexion-extension, and ankle inversion. Vertical joint forces were also significantly higher in the hip, knee, and ankle during simultaneous bilateral landing. Staggered foot landing showed higher muscle forces in the gluteus maximus, iliopsoas, and quadriceps femoris (p < 0.001). The EMG analysis revealed significant differences in the biceps femoris (p = 0.008) and quadriceps femoris (p < 0.001). These findings suggest that simultaneous bilateral landing increases joint load, while staggered foot landing increases muscle activation, which may lead to different injury risks between the two techniques. Full article

The demand for remote rehabilitation is increasing, opening up convenient and effective home-based therapy for the sick and elderly. In this study, we use AnyBody simulations to analyze muscle activity and determine key parameters for designing a rehabilitation exoskeleton, as well as selecting the appropriate motor torque to assist patients during rehabilitation sessions. The exoskeleton was designed with a PID control mechanism for the precise management of motor positions and joint torques, and it operates in both automated and teleoperation modes. Hip and knee movements are monitored via smartphone-based IMU sensors, enabling real-time feedback. Bluetooth communication ensures seamless control during various training scenarios. Our study demonstrates that remotely controlled rehabilitation systems can be implemented effectively, offering vital support not only during global health crises such as pandemics but also in improving the accessibility of rehabilitation services in remote or underserved areas. This approach has the potential to transform the way physical therapy can be delivered, making it more accessible and adaptable to the needs of a larger patient population. Full article

Backgroud: The main function of the hamstring muscles is to bend the knee joint and support the function of the hip extensors. Their frequent injuries are the result of overload related to, among others, dynamic running or jumping, and inadequate preparation for athletics activities. The asymmetry of the work of individual flexor muscle groups is clearly marked in the case of valgus or varus of the knee joint, i.e., in different positions of the lower limb. The aim of the study was to determine the position and form of a rehabilitation exercise in which an isolated group of muscles flexing the knee joint will show the greatest bioelectrical activity. Methods: The study involved 25 students of the Jagiellonian University Medical College. The students were aged 20–26. The average age was 22.9 (±1.4). The study participants included 17 women with an average age of 23.0 (±1.1) and 8 men with an average age of 22.6 (±1.9). Women constituted 68% and men 32% of all respondents. All participants agreed to participate in the study. Surface electromyography measurements in both lower limbs provided an initial number of 50 cases. The activity of the knee flexor muscles during isometric contraction with resistance was measured in correlation with three foot and lower leg settings: internal rotation, neutral position, and external rotation. The bioelectrical activity of the semitendinosus muscle is significantly higher (p < 0.01) in the internal rotation position than in the neutral position of the lower leg, while the bioelectrical activity of the biceps femoris muscle is inversely higher (p < 0.01) in the external rotation position than in the neutral position. Results: The results are significant for both average and maximum values of muscle stimulation. During isometric contraction with resistance, the semitendinosus muscle shows the greatest bioelectrical activity in the internal rotation position of the lower leg and foot, and the biceps femoris muscle in the external rotation position of the lower leg and foot. Conclusions: The above information has important implicational applications when improving isolated groups of hamstrings. In the future, this may contribute to more effective rehabilitation of patients with injuries of the muscles described in the article. Full article

Background and Objectives: Total hip arthroplasty (THA) requires accurate implant placement to ensure optimal outcomes. In this study, the AR Hip navigation system, an imageless portable navigation tool using augmented reality (AR), was evaluated for measuring radiographic inclination (RI), anteversion (RA), leg lengthening (LL), and offset (OS) changes in supine and lateral decubitus THA. Notably, this is the first report to assess the accuracy of LL and OS measurements using AR technology. Methods: We analyzed 48 hips from primary THA patients: 17 in the supine (S) group and 31 in the lateral (L) group. RI, RA, LL, and OS were measured intraoperatively using AR Hip and postoperatively using Zed Hip 3D software (Version 18.0.0.0). The absolute errors and outlier rates (≥5° for RI/RA and ≥5 mm for LL/OS) were compared between groups. Results: The mean intraoperative RI values with AR Hip were 40.1 ± 0.6° (S), 40.2 ± 1.2° (L), and 40.1 ± 1.0° (total), while the postoperative RI values with Zed Hip were 39.7 ± 2.9° (S), 39.5 ± 2.5° (L), and 39.6 ± 2.6° (total). The absolute errors were 1.8 ± 1.7° (total), with no significant group differences (p = 0.957). For RA, the errors were 2.0 ± 1.2° (total) (p = 0.771). The LL errors were 2.3 ± 2.2 mm (total) (p = 0.271), and the OS errors were 3.5 ± 2.8 mm (total) (p = 0.620). The outlier rates for RI were 11.8% (S) and 3.2% (L); for RA, 0% (S) and 3.2% (L); for LL, 29.4% (S) and 6.5% (L) with a significant difference (p = 0.031); and for OS, 23.5% (S) and 25.8% (L). No significant differences were observed for RI, RA, or OS. Conclusions: AR Hip provided accurate measurements of cup orientation, LL, and OS in both supine and lateral THA. Importantly, this study is the first to report the accuracy of LL and OS measurements using AR technology, demonstrating the potential of AR Hip for improving THA precision. Full article

Background and Objectives: Atherosclerosis, driven by dyslipidaemia and oxidative stress, is a leading cause of cardiovascular morbidity and mortality. This study evaluates the effects of vigorous-intensity bodybuilding exercise (VIBBE) on atherosclerosis biomarkers—including paraoxonase-1 (PON1) and arylesterase (ARE) activities—and lipid profiles in male bodybuilders who do not use anabolic-androgenic steroids. Comparisons were made with individuals engaged in moderate-intensity aerobic exercise (MIAE), as well as overweight/obese sedentary (OOS) and normal-weight sedentary (NWS) individuals. Materials and Methods: A cross-sectional study was conducted involving 122 healthy male participants aged 18–45 years, divided into four groups: VIBBE (n = 31), OOS (n = 30), MIAE (n = 32), and NWS (n = 29). Anthropometric assessments were performed, and fasting blood samples were collected for biochemical analyses, including lipid profiles and PON1 and ARE activities. Statistical analyses compared the groups and evaluated correlations between adiposity measures and atherosclerosis biomarkers. Results: The VIBBE group exhibited significantly lower levels of low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), and logarithm of the TG to high-density lipoprotein cholesterol (HDL-C) ratio [log(TG/HDL-C)] compared to the OOS group (p < 0.05 for all), indicating improved lipid profiles. However, these improvements were not significant when compared to the NWS group (p > 0.05), suggesting that VIBBE may not provide additional lipid profile benefits beyond those associated with normal weight status. PON1 and ARE activities were significantly lower in the VIBBE group compared to the MIAE group (p < 0.05 for both), suggesting that VIBBE may not effectively enhance antioxidant defences. Correlation analyses revealed significant inverse relationships between PON1 and ARE activities and adiposity measures, including body mass index (BMI), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), body fat percentage (BFP), fat mass index (FMI), and obesity degree (OD) (p < 0.05 for all). Positive correlations were observed between oxLDL and log(TG/HDL-C) and adiposity measures (p < 0.05 for all). Conclusions: Vigorous-intensity bodybuilding exercise improves certain lipid parameters compared to sedentary obese individuals but does not significantly enhance antioxidant enzyme activities or further improve lipid profiles beyond those observed in normal-weight sedentary men. Conversely, moderate-intensity aerobic exercise significantly enhances PON1 and ARE activities and improves lipid profiles, offering superior cardiovascular benefits. These findings underscore the importance of incorporating moderate-intensity aerobic exercise into physical activity guidelines to optimize cardiovascular health by balancing improvements in lipid metabolism with enhanced antioxidant defences. Full article

Objective: This study investigates the impact of age and knee osteoarthritis (OA) on the coronal plane alignment of the lower extremity in Japanese males and females, utilizing the Coronal Plane Alignment of the Knee (CPAK) classification system. Methods: A cross-sectional analysis was conducted with 150 male and 150 female patients. Participants were divided into three groups according to age and OA progression. The mechanical lateral distal femoral angle (mLDFA) and mechanical medial proximal tibial angle (mMPTA) were measured using standard digital long-leg radiographs. Arithmetic hip-knee-ankle angle (aHKA) and joint line obliquity (JLO) were calculated, and the CPAK classification was performed to verify the distribution among the three groups. Results: The results showed increased varus alignment of the mean mLDFA correlated with OA in both genders and with aging in males. The mean mMPTA did not change in males but shifted toward varus in females with both aging and OA. Both genders demonstrated a constitutional varus alignment with the progression of osteoarthritis (males: 1.3 ± 2.4° to −3.5 ± 3.7°, p < 0.001; females: −1.2 ± 3.2° to −3.6 ± 2.9°, p < 0.001). However, this trend with aging was observed only in females (0.0 ± 2.5° to −1.2 ± 3.2°, p = 0.018). JLO maintained its apex distal position with aging and OA progression in all subjects. The study further revealed a notable transition from CPAK Type II to Type I with OA progression in both genders, additionally influenced by aging in females. Conclusions: Aging affects coronal alignment and CPAK classification differently across genders. With OA progression, there was a shift toward smaller aHKA, while JLO remained unchanged. Compared to other races, young Japanese people exhibit similar CPAK distributions, but distinct differences appear in OA-affected individuals, highlighting potential racial variations in CPAK classifications. Full article

The positive effects of whole-body vibration exercise in rehabilitation, sport, fitness and preventive medicine have led to a proliferation of vibrating platforms. However, discrepancies have been claimed between the manufacturers’ vibration parameters and the vibration applied by the platforms. In addition, the dimensions, materials and motors used in their manufacture mean that each platform behaves differently. These factors can influence their transmission to the human body and, consequently, their effects. Thus, measured vibration parameters were recommended to report the vibration parameters as accurately as possible. Therefore, the present study aimed to determine the feasibility of a large vibration platform. Measurements of vibration parameters and their transmission were added. These parameters were measured using six accelerometers (platform, ankle, knee, hip, third lumbar vertebra, and head) throughout five postures (toe-standing, erect, high squat, deep squat, and lunge) and three vibration frequencies (20 Hz, 25 Hz, and 30 Hz). On the platform, peak accelerations of 1 ± 0.2 g, displacements of 1 ± 0.1 mm at 20 Hz and 25 Hz and 0.6 mm at 30 Hz, and a frequency from the setting of +0.5 Hz were obtained. In the human body, peak accelerations can exceed 2 g, and these transmissibility amplifications were found at the ankles and knees. However, at the hip, accelerations plummet and transmissibility attenuation occurs all the way to the head. The signal purity was highly satisfactory, although at the hip and third lumbar vertebra when adopting the toe-standing and lunge, some less satisfactory results were found—especially at 20 Hz and 30 Hz. Present data indicate that the long vibration platform can be used for exercise and health in a safe way, although its specific behaviours have to be taken into account in order to optimise its applicability. Full article

An exoskeleton is a wearable device with human–machine interaction characteristics. An ideal exoskeleton should have kinematic and kinetic characteristics similar to those of the wearer. Most traditional exoskeletons are driven by rigid actuators based on joint torque or position control algorithms. In order to achieve better human–robot interaction, flexible actuators have been introduced into exoskeletons. However, exoskeletons with fixed stiffness cannot adapt to changing stiffness requirements during assistance. In order to achieve collaborative control of stiffness and torque, a bionic variable stiffness hip joint exoskeleton (BVS-HJE) is designed in this article. The exoskeleton proposed in this article is inspired by the muscles that come in agonist–antagonist pairs, whose actuators are arranged in an antagonistic form on both sides of the hip joint. Compared with other exoskeletons, it has antagonistic actuators with variable stiffness mechanisms, which allow the stiffness control of the exoskeleton joint independent of force (or position) control. A BVS-HJE model was established to study its variable stiffness and static characteristics. Based on the characteristics of the BVS-HJE, a control strategy is proposed that can achieve independent adjustment of joint torque and joint stiffness. In addition, the variable stiffness mechanism can estimate the output force based on the established mathematical model through an encoder, thus eliminating the additional force sensors in the control process. Finally, the variable stiffness properties of the actuator and the controllability of joint stiffness and joint torque were verified through experiments. Full article

Background/objectives: Both erosions and osteoporosis in rheumatoid arthritis (RA) have common mechanisms. The aim of this study was to evaluate the relationship between erosion and bone mineral density (BMD) in RA and whether it can be driven by autoimmunity. Methods: Patients fulfilling the ACR 1987- or ACR/EULAR 2010-criteriae for RA. performed radiographs (erosions evaluated by the modified Sharp/van der Heidje erosion score) and biology for anti-citrullinated peptide antibodies (ACPAs), rheumatoid factors (RFs) and anti-nuclear antibodies (ANAs) at intervals of less than 2 years from dual-energy X-ray absorptiometry (DXA) for BMD assessment. Results: A total of 149 patients were included, (75.8% women, mean age of 62 y.o (SD 9.61) and a median disease duration of 132 months [60; 240]). A total of 61.1% patients were ACPA positive, 79.9% were erosive and 10.7% had a hip or spine T-score ≤ −2.5. A higher erosion score was associated with a lower BMD (value: −0.222; p = 0.009) and T-score (value −0.397; p < 0.0001) in the hip. ACPA status was associated with a higher erosion score (63.0 (53.2) vs. 45.5 (44.1) for ACPA- (p = 0.04)). ACPA titers were associated with a lower BMD in the hip (value −0.216; p = 0.01). In linear regression, erosion and BMD were still associated, but this association is not driven by ACPA status or titer. Conclusions: In RA patients, erosions and BMD are inversely associated but this relationship does not seem to be driven by autoimmunity only. However, the presence of ACPA or erosion should lead to osteoporosis screening. Full article